iRacing oval physics are getting a major update in Season 2. The changes target rubber buildup, rubber distribution, and the drafting model for the NASCAR O’Reilly Series. The Dallara IR18 IndyCar also receives updated aerodynamics, tire construction, and engine power figures. iRacing frames the iRacing oval physics rubber system as a multi-season project, with Season 2 representing the first major step.
iRacing Oval Physics: NASCAR Drafting Gets a CFD Upgrade
Additionally, the drafting model update for NASCAR O’Reilly Series cars uses CFD (Computational Fluid Dynamics) data. Side-drafting now produces more nuanced effects. Car-to-car variability in tight quarters feels more realistic. These changes matter most at superspeedways and larger ovals where pack racing is common. Drivers should notice a different feel when racing in close proximity to other cars.
Rubber Buildup Gets a Realistic Overhaul
In particular, the rubber improvements address a separate aspect of oval racing realism. Real oval tracks develop a distinct rubber layer on the racing line during green-flag runs. Tires then pick up less rubber during cautions and light running. iRacing is now modeling how much rubber accumulates under heavy use and how that buildup changes grip across the track surface. This affects strategy decisions around tire management and pit timing.
Furthermore, these iRacing oval physics changes set up a multi-season improvement path. Specifically, the rubber system will continue evolving in future builds. Additionally, the CFD drafting model could expand to other oval series beyond the O’Reilly cars. Meanwhile, the IndyCar aero and power updates should produce noticeably different racing at superspeedways. As a result, oval racers have a lot to look forward to beyond just Season 2. Indeed, this is the most significant oval physics investment iRacing has made in several seasons.
Specifically, the oval physics updates arrive in iRacing with the Season 2 build on March 10, 2026. See the full iRacing development update for more details.
